SAT-451 - Caught in an Endocrine Storm: A Rare Presentation of Severe Hypercalcemia and Takotsubo Cardiomyopathy Due to Acute Adrenal Crisis in Autoimmune Polyglandular Syndrome Type 2

Autoimmune polyglandular syndrome type 2 is defined by the coexistence of primary adrenal insufficiency with autoimmune thyroid disease and/or type 1 diabetes mellitus. Acute adrenal crisis is a life-threatening manifestation, typically presenting with profound hypotension, gastrointestinal symptoms, and altered mentation. Hypercalcemia in adrenal insufficiency is uncommon, with a prevalence of 5.5% to 6% [1-3]. Early recognition is critical since adrenal crisis has a mortality rate of up to 6%. This case highlights the importance of recognizing adrenal insufficiency as a differential diagnosis of hypercalcemia to decrease the mortality of adrenal crisis.

A 44-year-old woman with a five-year history of primary hypothyroidism and secondary amenorrhea presented to the ED with severe nausea, vomiting, fatigue, weight loss, and persistent hypotension requiring intravenous fluid resuscitation and vasopressor support. She was noted to have severe hypercalcemia and acute renal insufficiency with calcium 14.2 mg/dL, albumin 4.1 g/dL, eGFR 31 mL/min/1.73 m², and sodium 128 mmol/L Parathyroid hormone was suppressed < 6 pg/mL, 1,25 dihydroxyvitamin D was low < 8 pg/mL, PTH-related peptide was normal at 15 pg/ml (11-20), 25-hydroxyvitamin D was 30 ng/mL, and troponin was elevated at 874 ng/L ( < 11). She received intravenous fluids and vasopressors. Hydrocortisone 100 mg IV three times daily was initiated and later reduced to 50 mg three times daily. After cortisol was < 0.2 µg/dL, fludrocortisone 0.1 mg daily was started. Hypercalcemia and renal insufficiency were resolved. Coronary angiography revealed normal coronaries, and adrenal CT was unremarkable. She was discharged on hydrocortisone 10 mg in the morning and 5 mg at night, and fludrocortisone 0.1 mg daily.

Outpatient evaluation three months later revealed skin hyperpigmentation preceding steroid therapy. Cortisol remained suppressed < 0.2 µg/dL [5–25], DHEA-sulfate was undetectable < 5 µg/dL [35–430], aldosterone was < 1 ng/dL with normal renin, and calcium and renal function were normal. ACTH was markedly elevated at 6224 pg/mL (7-63) with positive 21-hydroxylase antibodies, confirming autoimmune primary adrenal insufficiency.

Hypercalcemia is an uncommon presentation of adrenal insufficiency and is typically mild, with prior reports largely limited to secondary adrenal insufficiency and calcium levels < 11 mg/dL [4-6]. Our case represents the first reported presentation of adrenal insufficiency with severe hypercalcemia, hypovolemic shock, and Takotsubo cardiomyopathy. Takotsubo cardiomyopathy has been described during adrenal crisis, likely precipitated by metabolic derangements and catecholamine excess.

This case underscores the broad clinical spectrum of adrenal insufficiency and its importance as a critical diagnostic consideration in severe hypercalcemia.

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